While proceeding biochemical experiments at normal hospitals in the earlier times, a syringe tube in general is always used for blood-gathering of a human body, then filling the blood from the syringe tube into a test tube (i.e. the blood-gathering tube) in order to proceed with the examinations or biochemical experiments. In this course, except each syringe tube and test tube for use, the blood of human body has to be filled into the test tube through the syringe tube, so the probability of blood pollution and operating cost of the medical personnel are increased.
The blood-gathering device disclosed in Taiwan Utility Model Patent No. 25838 (Application No. 7222395) consists of a needle holder, a syringe tube, a piston and puller, making use of pulling motion of the puller and piston for blood-gathering. When blood-gathering is finished, the puller is removed through turning it counterclockwise. After removing its injection needle head, a cover is screwed onto the needle holder so that the syringe tube becomes a test tube for storing the blood. Because its structure is in need of such elements as a piston, a puller, etc., it is difficult to lower its cost. After blood-gathering is finished, the puller has to be removed with a specific process and a cover has to be screwed onto the needle holder, such a follow-up process will increase the working burden of medical personnel.
In view of the above, some manufacturers have developed a vacuum blood-gathering tube 10 as shown in FIG. 1 in matching with an injection needle jacket 20 as shown in FIG. 2 for blood-gathering. As shown in FIG. 1, the vacuum blood-gathering tube 10 comprises a tube body 11 and an elastic cork 12. The tube body 11 is normally made of glass or transparent resin with better air-tight property. However, the tube body made of resin remains poorer than glass in the aspect of air-tightness and is rather difficult to keep the condition of long-term vacuum, and tends to breach and is detrimental to shipping and storage. One end of the tube body 11 is closed and another end is an opening. The elastic cork 12 is normally made of synthetic rubber. So far as the vacuum blood-gathering tube 10 is concerned, the elastic cork is tightly nested in the opening of tube body 11 in a vacuum low-pressure environment so as to maintain a condition of vacuum low-pressure in the tube body 11.
As shown in FIG. 2, the injection needle jacket 20 comprises a sleeve 21 and a needle head 22. One end of the sleeve 21 is provided with a threaded hole 211 and another end is an opening 212. The outer edge in the middle section of needle head 22 is provided with a thread 221. Two ends 222 and 223 of the needle head 22 are shaped as sharp, and the thread 221 in the middle section of needle head 22 is screwed into the threaded hole 211 of sleeve 21 so that one end 222 of the needle head 22 is outside the threaded hole 211 of sleeve 21 for thrusting into the blood vessel of a human body, and another end 223 is on the inner edge of sleeve 21 and able to pierce through the elastic cork 12 of vacuum blood-gathering tube 10.
When blood-gathering, to thrust one end 222 of needle head 22 of injection needle jacket 20 into the blood vessel of human body, then to nest the vacuum blood-gathering tube 10 into the sleeve 21 of injection needle jacket 20, another end 223 of the needle head 22 in the sleeve 21 pierces through the elastic cork 12 of vacuum blood-gathering tube 10 and enters into the tube body 11 in a state of vacuum low-pressure, making use of low pressure in the tube body 11 attracts blood of human body to flow into the tube body 11. After blood-gathering is finished, to remove the vacuum blood-gathering tube 10 from the injection needle jacket 20. Since the needle hole wall formed on the elastic cork 12 by thrusting the needle head 22 into the vacuum blood-gathering tube 10 can stretch and restore its closed state at once to release pressure from it after the needle head 22 disengages from the elastic cork 12, the blood in the vacuum blood-gathering tube 10 will never be polluted or exude out from the needle hole.
The vacuum blood-gathering tube 10 tightly nested at the opening of tube body 11 and made of glass or transparent resin in a low-pressure environment as shown in Fig. 1 will not be fully air-tight and usable because it is stored for a long time (even up to 2-3 years) or the elastic cork 12 is not tightly nested into the tube body 11. Therefore, almost all of the manufacturers use the glass tube body with better air-tightness waive the cheaper tube body made of transparent resin or other plastic materials. The air-tightness of tube body made of glass is better but tends to breach because of a slight collision during shipping or storage and is possible to leak air for its long storage time or inadequate air-tightness of nesting the elastic cork into the tube body.